M58LT128GST datasheet(22/98 Pages) STMICROELECTRONICS

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4 Command Interface

M58LT128GST, M58LT128GSB

22/98

See Appendix C, Figure 19: Program Flowchart and Pseudo Code, for the flowchart for using

the Program command.

4.8

Buffer Program command

The Buffer Program Command makes use of the device’s 32-Word Write Buffer to speed up

programming. Up to 32 Words can be loaded into the Write Buffer. The Buffer Program

command dramatically reduces in-system programming time compared to the standard non-

buffered Program command.

Four successive steps are required to issue the Buffer Program command.

The first Bus Write cycle sets up the Buffer Program command. The setup code can be

addressed to any location within the targeted block.

After the first Bus Write cycle, read operations in the bank will output the contents of the

Status Register. Status Register bit SR7 should be read to check that the buffer is

available (SR7 = 1). If the buffer is not available (SR7 = 0), re-issue the Buffer Program

command to update the Status Register contents.

The second Bus Write cycle sets up the number of Words to be programmed. Value n is

written to the same block address, where n+1 is the number of Words to be programmed.

Use n+1 Bus Write cycles to load the address and data for each Word into the Write

Buffer. Addresses must lie within the range from the start address to the start address + n.

Optimum performance is obtained when the start address corresponds to a 32 Word

boundary. If the start address is not aligned to a 32 word boundary, the total programming

time is doubled

The final Bus Write cycle confirms the Buffer Program command and starts the program

operation.

All the addresses used in the Buffer Program operation must lie within the same block.

Invalid address combinations or failing to follow the correct sequence of Bus Write cycles will

set an error in the Status Register and abort the operation without affecting the data in the

memory array.

If the Status Register bits SR4 and SR5 are set to '1', the Buffer Program Command is not

accepted. Clear the Status Register before re-issuing the command.

If the block being programmed is protected an error will be set in the Status Register and the

operation will abort without affecting the data in the memory array.

During Buffer Program operations the bank being programmed will only accept the Read Array,

Read Status Register, Read Electronic Signature, Read CFI Query and the Program/Erase

Suspend command, all other commands will be ignored.

Refer to Dual Operations section for detailed information about simultaneous operations

allowed in banks not being programmed.

See Appendix C, Figure 20: Buffer Program Flowchart and Pseudo Code, for a suggested

flowchart on using the Buffer Program command.

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